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At least 865 records · Page 48Linked to original sources
PubMed1987

ARTS: a flexible laboratory instrument control language.

A generalized computer program, ARTS (Analytical Robot Telecommunications Software), has been developed to give the research scientist more flexible control of laboratory robots and instruments. As a stand-alone program, ARTS is a complete laboratory control language. ARTS can also be an extension of other software in either a master or slave mode. As master, ARTS can call on other software to perform certain tasks. In a slave mode, ARTS can act as a sensory extension of the calling software. ARTS is a flexible laboratory control language capable of adapting to changing laboratory requirements.

Laboratories↗
PubMed2002

Multichannel digital transmission in an optical network of communicating molecules.

In present telecommunication networks, information transfer relies on the interplay of optical and electrical signals. Data are communicated optically but processed electronically. Methods to maintain the propagating signals solely at the optical level must be developed to overcome the transmission capacities and speed limits imposed by the electronic components. We have demonstrated that molecular switches can be used to gate optical signals in response to optical signals. We have realized a simple optical network consisting of three light sources, one cell containing a solution of three fluorescent molecules, one cell containing a solution of a three-state molecular switch and a detector. The light emitted by the three fluorophores is absorbed by the three states of the molecular switch. Using this simple operating principle, we have shown that multichannel digital transmission can be implemented on an ensemble of communicating molecules relying exclusively on the interplay of optical inputs and optical outputs.

Journal Article↗
PubMed2002

Unusual frequency dispersion effects of the nonlinear optical response in highly conjugated (polypyridyl)metal-(porphinato)zinc(II) chromophores.

The syntheses and electrooptic properties of a new family of nonlinear optical chromophores are reported. These species feature an ethyne-elaborated, highly polarizable porphyrinic component and metal polypyridyl complexes that serve as integral donor and acceptor elements. Examples of this structural motif include ruthenium(II) [5-(4'-ethynyl-(2,2';6',2' '-terpyridinyl))-10,20-bis(2',6'-bis(3,3-dimethyl-1-butyloxy)phenyl)porphinato]zinc(II)-(2,2';6',2' '-terpyridine)(2+) bis-hexafluorophosphate (Ru-PZn); osmium(II) [5-(4'-ethynyl-(2,2';6',2''-terpyridinyl))-10,20-bis(2',6'-bis(3,3-dimethyl-1-butyloxy)phenyl)porphinato]zinc(II)-(2,2';6',2''-terpyridine)(2+) bis-hexafluorophosphate (Os-PZn); ruthenium(II) [5-(4'-ethynyl-(2,2';6',2''-terpyridinyl))-15-(4'-nitrophenyl)ethynyl-10,20-bis(2',6'-bis(3,3-dimethyl-1-butyloxy)phen-yl)porphinato]zinc(II)-(2,2';6',2' '-terpyridine)(2+) bis-hexafluorophosphate (Ru-PZn-A); osmium(II) [5-(4'-ethynyl-(2,2';6',2' '-terpyridinyl))-15-(4'-nitrophenyl)ethynyl-10,20-bis(2',6'-bis(3,3-dimethyl-1-butyloxy)phenyl)porphinato]zinc(II)-(2,2';6',2' '-terpyridine)(2+) bis-hexafluorophosphate (Os-PZn-A); and ruthenium(II) [5-(4'-ethynyl-(2,2';6',2' '-terpyridinyl))osmium(II)-15-(4'-ethynyl-(2,2';6',2''-terpyridinyl))-10,20-bis (2',6'-bis(3,3-dimethyl-1-butyloxy)phenyl)porphinato]zinc(II)-bis(2,2';6',2''-terpyridine)(4+) tetrakis-hexafluorophosphate (Ru-PZn-Os). The frequency dependence of the dynamic hyperpolarizability of these compounds was determined from hyperRayleigh light scattering (HRS) measurements carried out at fundamental incident irradiation wavelengths (lambda(inc)) of 800, 1064, and 1300 nm. These data show that (i) coupled oscillator photophysics and metal-mediated cross-coupling can be exploited to elaborate high beta(0) supermolecules that exhibit significant excited-state electronic communication between their respective pigment building blocks; (ii) high-stability metal polypyridyl compounds constitute an attractive alternative to electron releasing dialkyl- and diarylamino groups, the most commonly used donor moieties in a wide range of established nonlinear optical dyes; (iii) this design strategy enables ready elaboration of chromophores having extraordinarily large dynamic hyperpolarizabilities (beta(lambda) values) at telecommunication relevant wavelengths; and (iv) porphyrin B- and Q-state-derived static hyperpolarizabilities (beta(0) values) can be designed to have the same or opposite sign in these species, thus providing a new means to regulate the magnitude of lambda(inc)-specific dynamic hyperpolarizabilities.

Journal Article↗
PubMed2003

Colloidal crystal films: advances in universality and perfection.

For three-dimensional photonic crystals, made either by top-down microfabrication or by bottom-up self-assembly approaches, to comply with the stringent requirements of optical telecommunication applications, their degree of structural perfection and optical quality must meet an exceptionally high standard. Only with such superior quality photonic crystals can their unique optical properties be harnessed in optical devices and circuits constructed from micrometer-sized optical components. In this paper, we present a new strategy for making silica colloidal crystal films with a sufficiently high level of structural perfection and optical quality to make it competitive as a practical route to photonic crystal optical components. The attainment of this goal takes due cognizance of three key synergistic factors in the film formation process. The first recognizes the necessity to prepare high-quality silica spheres, which are highly monodisperse, with a polydispersity index significantly better than 2%, and the second recognizes that the population of spheres must be devoid of even the smallest fraction of substantially smaller or larger spheres or sphere doublets. The latter turns out to have a minimal effect on the polydispersity index, and yet a major detrimental effect on the overall structural order of the film. The third concerns the film-forming method itself, which necessitated the development of a novel process founded upon isothermal heating evaporation-induced self-assembly (IHEISA) of spheres on a planar substrate. This new method has several advantages over previously reported ones. It is able to deposit very high-quality silica colloidal crystal film rapidly over large areas, with a controlled thickness and without any restrictions on sphere sizes.

Journal Article↗
PubMed2006

A low-temperature synthesis for organically soluble HgTe nanocrystals exhibiting near-infrared photoluminescence and quantum confinement.

A new low-temperature, one-pot method is introduced for the preparation of organically passivated HgTe nanocrystals, without the use of highly toxic precursors. The nanocrystals show bright photoluminescence in the infrared telecommunication windows about 1300 and 1550 nm with quantum efficiencies between 55 and 60%. They have a zinc blende structure with a mean particle diameter of 3.4 nm, thus exhibiting quantum confinement effects. Particle growth is self-limited by temperature quenching, so a narrow size distribution is obtained. The measured size of the particles agrees with calculations using the pseudopotential method.

Journal Article↗
PubMed2006

Bisdioxaborine polymethines with large third-order nonlinearities for all-optical signal processing.

Organic materials with large third-order nonlinearities in the near-infrared spectral regime are critical in the development of photonic devices to be utilized in all-optical signal processing. We have developed polymethine materials, specifically bisdioxaborine-terminated polymethine dyes, which possess large ultrafast third-order nonlinearities and low nonlinear loss all in the near-infrared spectral regime. An extended bisdioxaborine polymethine anion exhibited the largest value of gamma (third-order microscopic nonlinearity) at 1.3 mum (|gamma| = 5.7 x 10-32 esu) and showed no characteristics of symmetry breaking, unlike other polymethines of similar lengths. A neat film of this molecule maintained relatively low linear loss in the near-infrared and showed a large third-order macroscopic nonlinearity at 1.3 mum (|chi(3)| = 3.6 x 10-10 esu), with a temporal response of less than 8 ps. Furthermore, the real part of chi(3) was nearly an order-of-magnitude larger than the imaginary component. Consequently, this material exhibited good figures of merit for all-optical signal processing throughout the entire telecommunications band.

Journal Article↗
PubMed2006

Solvothermal synthesis of monodisperse PbSe nanocrystals.

Size-controllable monodisperse PbSe and PbSe/PbS nanocrystals (NCs) have been successfully synthesized with a solvothermal method. Octadecylamine (ODA) molecules were found effective in organizing the nanocrystals to form an ordered monolayer. It is expected that these narrow-band-gap semiconductor NCs with tunable size would have potential applications in near- and mid-IR telecommunication laser sources, electroluminescence, and solar cell materials.

Journal Article↗
PubMed2005

Property and morphology development in nanocomposite thermoplastic elastomer gels.

Thermoplastic elastomer gels (TPEGs), molecular networks composed of a microphase-separated multiblock copolymer swollen to a large extent by a low-volatility midblock-selective solvent, are ubiquitous in a wide range of contemporary technologies, including home and office products, athletic equipment, and telecommunications devices. In this work, we investigate the effect of several network-forming nanoscale modifiers-two different silica nanoparticles, three different nanoclays, and a multiwalled carbon nanotube-on the property and morphology development of a TPEG prepared from a microphase-ordered poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) triblock copolymer imbibed with an EB-compatible aliphatic mineral oil. Dynamic rheological measurements of the resultant nanocomposite TPEGs confirm that addition of these modifiers affects the linear viscoelastic threshold and increases, to different extents, the dynamic elastic modulus, the dynamic yield stress, and the maximum operating temperature of the parent TPEG. X-ray diffraction analysis reveals that the nanoclays used to generate three series of modified TPEGs are generally swollen with copolymer and/or solvent.

Journal Article↗
PubMed2006

Metallic photonic crystals based on solution-processible gold nanoparticles.

We demonstrate the fabrication of metallic photonic crystals, in the form of a periodic array of gold nanowires on a waveguide, by spin-coating a colloidal gold suspension onto a photoresist mask and subsequent annealing. The photoresist mask with a period below 500 nm is manufactured by interference lithography on an indium tin oxide (ITO) glass substrate, where the ITO layer has a thickness around 210 nm and acts as the waveguide. The width of the nanowires can be controlled from 100 to 300 nm by changing the duty cycle of the mask. During evaporation of solvent, the gold nanoparticles are drawn to the grooves of the grating with apparently complete dewetting off the photoresist for channels less than 2 microm in width, which therefore form nanowires after the annealing process. Strong coupling between the waveguide mode and the plasmon resonance of the nanowires, which is dependent on the polarization and incidence angle of the light wave, is demonstrated by optical extinction measurements. Continuity of the nanowires is confirmed by conductivity properties. Simplicity, high processing speed, and low cost are the main advantages of this method, which may have a plethora of applications in telecommunication, all-optical switching, sensors, and semiconductor devices.

Crystallization↗
PubMed2000

Telehealth in the Pacific: current status and analysis report (1999-2000).

From the summer of 1999 to the spring of 2000, we undertook an on-site investigation of the management and operational status of telehealth in the Pacific. The writers also gathered additional materials upon returning to Japan to provide as detailed a report as possible on the current status and analysis of telemedicine in the Pacific. Following the collapse of the Soviet Union, various regions around the world has sought a gentler alternative to "deterrence by arms." The writers of this paper believe one such means is telemedicine. We believe telemedicine services may help offset the emotional stress and sense of inequality experienced by "islanders and civilians living around military bases," which the financial benefits of the so-called "base-economy" alone has never been able to remedy. There are numerous medical support activities currently operating in the Pacific region, and telecommunications is the most effective tool for connecting and unifying such a vast region. We believe that projects for this region must have a clear focus and objective and be able to demonstrate concrete results in order to win subsidies or aid.

Developing Countries↗
PubMed1998

Internet teleconferencing as a clinical tool for anesthesiologists.

Internet teleconferencing software can be used to hold "virtual" meetings, during which participants around the world can share ideas. A core group of anesthetic medical practitioners, largely consisting of the Society for Advanced Telecommunications in Anesthesia (SATA), has begun to hold regularly scheduled "virtual grand rounds." This paper examines currently available software and offers impressions of our own early experiences with this technology. Two teleconferencing systems have been used: White Pine Software CU-SeeMe and Microsoft NetMeeting. While both provided acceptable results, each had specific advantages and disadvantages. CU-SeeMe is easier to use when conferences include more than two participants. NetMeeting provides higher quality audio and video signals under crowded network conditions, and is better for conferences with only two participants. While some effort is necessary to get these teleconferencing systems to work well, we have been using desktop conferencing for six months to hold virtual Internet meetings. The sound and video images produced by Internet teleconferencing software are inferior to dedicated point-to-point teleconferencing systems. However, low cost, wide availability, and ease of use make this technology a potentially valuable tool for clinicians and researchers.

Anesthesiology↗
PubMed2001

Biofeedback via telehealth: a new frontier for applied psychophysiology.

Psychophysiological diagnostic and therapeutic methods, to include biofeedback, have been found to be empirically effective in the treatment of a variety of physical disorders. In many areas of the country, however, certified biofeedback practitioners are not well distributed, limiting patient access to this treatment modality. Psychologists at Tripler Army Medical Center have pioneered efforts to develop and provide these needed services via a telehealth venue. Such capability significantly improves access to care, particularly for patient's located at considerable distance from the provider. As the telecommunications infrastructure in rural and remote areas is often quite basic, such a system must be capable of operating within these limited parameters. The system developed by the authors provides real-time video and audio interactivity and allows the therapist to monitor and control biofeedback equipment located at the remote site. The authors discuss the clinical applications, the technology, and relevant practical and ethical issues.

Biofeedback, Psychology↗
PubMed2002

Economic effects and spin-offs in a small space economy: the case of Canada.

Canada, through a well-focused space program (telecommunications, earth observation, robotics), has succeeded in developing a space industry largely based on SMEs. The result has been significant economic benefits and technological spin-offs. In this article, the results of two programs, the ESA (European Space Agency) and the STEAR (Strategic Technologies in Automation and Robotics), are compared. The ESA program has generated significant indirect effects and spin-offs for Canadian exports. ESA's reputation and network have enabled SMEs to increase export sales of both space products and other commercial products derived from space technologies. The STEAR program has been highly successful in promoting a new generation of SMEs for space robotics, encouraging both spin-in and spin-offs of technologies. The analysis highlights the complementarity of mission- and diffusion-oriented programs in the technology transfer process.

Canada↗
PubMed1999

Tele-education in a telemedicine environment: implications for rural health care and academic medical centers.

Over 50 million people in the United States (about 20% of the population) live in rural areas, but only 9% of the nation's physicians practice in rural communities. It is difficult to recruit and retain rural health care practitioners, partly because of issues relating to professional isolation. New and enhanced telecommunications links between community and academic hospitals show promise for reducing this isolation and enhancing lifelong learning opportunities for rural health care providers. This paper will explore some of the issues involved in using interactive video (telemedicine) networks to transmit continuing medical education programming from an academic center to multiple rural hospitals. Data from a recent University of Iowa survey of the state's health educators will be presented as one approach to assessing the health care marketplace for the deployment of tele-education services.

Academic Medical Centers↗
PubMed1999

[Telematic and surgery: methods, terminology and instructions].

BACKGROUND: Telematic is the application of computer technology in modern telecommunication. Telemedicine will be of growing importance in the international collaboration in surgery. OBJECTIVE: Review of the different telematic applications for surgery and presentation of technology and tools. Practical user's guide. METHOD: Analysis of our international network of telesurgical staff meetings between 6 University Hospitals. Review of the situation of telemedicine in Switzerland and around the world. RESULTS: After performing some comparative tests we chose to work with 6 ISDN channels at the world wide standard H.320 (rate of 384 Kb/s) which is widely available in Switzerland and around the world. Technical options, market opportunities and relationship between needs and goals of telemedicine are presented on a user point of view. DISCUSSION: More than 70 telesurgical staff meetings allowed us to get an overview of this technology, in order to benefit of telemedicine applications for teaching and clinical use. Important factors are the analysis of needs and goals prior to the teleconference. CONCLUSION: Consultation, second opinion, teaching and training should be new clinical applications of telemedicine, leading to an increase of surgical quality control in Europe and in the world.

Computer Communication Networks↗
PubMed2001

Eastern Caribbean family psychology with conduct-disordered adolescents from the Virgin Islands.

Family psychology is a new and relatively undeveloped discipline in much of the English-speaking Caribbean, particularly in the U.S. Virgin Islands. Family structure and youth behavior in the region have changed dramatically over the past few decades. Given the family-oriented nature of the culture, it is posited that the use of family psychology as an approach to research and intervention may prove to be a rich method to address this cultural metamorphosis. This article examines the potential effectiveness of interventions at the family level when mental health providers are working with youth with conduct disorder in the Virgin Islands. This article is offered as a microcosm of the global changes in family structure and the youth culture that are occurring particularly in the developing world, in part due to the rapid development of telecommunications. Possible roles of the family psychologist in this global transformation are presented.

Adolescent↗
PubMed2007

Antecedents and outcomes of abusive supervision: test of a trickle-down model.

The authors examined antecedents of abusive supervision and the relative importance of interactional and procedural justice as mediators of the relationship between abusive supervision and the work outcomes of affective organizational commitment and individual- and organization-directed citizenship behaviors. Data were obtained from subordinate-supervisor dyads from a telecommunication company located in southeastern China. Results of moderated regression analysis revealed that authoritarian leadership style moderated the relationship between supervisors' perceptions of interactional justice and abusive supervision such that the relationship was stronger for supervisors high rather than low in authoritarian leadership style. In addition, results of structural equation modeling analysis revealed that subordinates' perceptions of interactional but not procedural justice fully mediated the relationship between abusive supervision and the work outcomes. Implications for future investigations of abusive supervision are discussed.

Authoritarianism↗
PubMed1970

Frequencies for radio astronomy.

At present the scope of research in radio astronomy is limited by the allocation of frequencies, some of which have to be shared with other radio services. When the International Telecommunications Union reconsiders all frequency allocations next year, astronomers are hoping for an improvement.

Journal Article↗